The present invention relates to a gas pressure circuit breaker having a break gap formed by two fixed contacts and having an insulation tube surrounding the gap at least at times and further having sheath-side passage openings for the distribution of a quenching gas flowing into the break gap.
Such a gas pressure circuit breaker is known, for instance, from DE-PS No. 26 47 643. In this circuit breaker the break gap is surrounded, in the course of the breaking movement, by a thin-walled insulation tube, whose sheath-side passage openings for the quenching gas are formed, for example, by rectangular slits extending in azimuthal direction to the insulation tube, the slits being separated by webs extending in the axial and azimuthal direction. The webs are under the thermal stress of an arc drawn during breaking, from the interior of the insulation tube, and even when arc-resistant materials, such as PTFE, are used, they are mechanically weakened by the inevitable burnoff, so that the stability of the insulation tube may be reduced.